1. Field of the Invention
The present invention relates to a Universal Serial Bus (USB) unit for connecting an electrical/electronic product of a personal computer or the like and a peripheral device. This application is based on Japanese Patent Application No. Hei 11-82524, the contents of which are incorporated herein by reference.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
A Universal Serial Bus (USB) is an interface standard for connecting a personal computer and a peripheral device, and is adopted in almost all new machines with Window 98® installed. According to the USB, a keyboard, a mouse, a modem, and the like can be easily connected to a computer with one interface and parts or the like can have low cost. The peripheral devices which can be connected with the personal computer include a keyboard, a mouse, a scanner, a modem, or the like, having a relatively rapid data transfer rate, and they are connected through a tree structure to a personal computer using the USB unit. Furthermore, if a conversion circuit is arranged in the USB unit, peripheral units such as a high-speed printer can be connected to the personal computer.
In conventional kinds of these USB units, USB port bars, and the like, various conversion circuits and external interfaces are integrated in a USB unit. An example is shown in FIG. 9.
Since a USB unit 100 is connected to an electrical/electronic device 102 with a USB cable 103, a USB controller 111 in the electrical/electronic device 102 is connected to a USB_HUB 105 in the USB unit 100. After conversion circuits 106-1, 106-2, 106-3, and 106-4 are connected to the USB_HUB 105 and each USB signal 114 is converted to each interface signal for a peripheral device in each conversion circuit, each interface signal is transmitted to the peripheral devices 107-1, 107-2, 107-3, and 107-4 through the external interface correctors 109-1, 109-2, 109-3, and 109-4 respectively. Basically, in one USB unit, conversion circuits and external interface connectors for various peripheral devices are arranged.
If an external USB connector 110 is arranged in the USB unit 100, an exterior type USB unit 108 can be connected to the USB unit 100 using the external USB connector 110 and a USB cable 103.
Moreover, to reduce inconveniences caused by a cable at the time of connecting peripheral equipments with each other by constituting a connection means provided on one peripheral equipment, a USB hub is connected with a USB connector through the cable and is provided with a connector for a mouse and a keyboard and the connector for a power supply in a projected shape and the connector for data signal transmission on an upper surface similarly to a floppy disk drive device. Thus, the respective connectors further provided on the upper surface of the USB hub and the respective connectors provided on the bottom surface of the peripheral equipment, it is mounted on it and the respective connectors are fitted with each other (disclosed in Japanese Unexamined Patent Application, First Publication, No. Hei 10-240382.)
And further, a device is equipped with a USB hub, connected to a computer device equipped with a root hub, which has an up-string port UP1 that is so controlled as to display information, equipped with a power supply part, and connected to the root hub of the computer device, and down-string ports DP1 to DP3 which receive power source switching information from the computer through the up-string port and selectivity outputs the electric power supplied from the power supply part, to enable a user to easily install the peripheral equipment (disclosed in Japanese Unexamined Patent Application, First Publication, No. Hei 10-116139.)
Furthermore, to eliminate defects due to providing a connection portion of a peripheral device on the backside of a CPU, a monitor base is constituted as a serial bus hub supporting a monitor rotationally and having plural ports for interface with a peripheral device such as a keyboard and a mouse. When the peripheral device is connected to the port, it is connected to a serial bus via serial bus output connecting means, and thereby the peripheral device can communicate with a CPU. Since there is no need for connecting the peripheral device to the backside of the CPU, cable connection and maintenance are facilitated, and the cable can be prevented from being caught (disclosed in Japanese Unexamined Patent Application, First Publication, No. Hei 10-154560.)
However, conventional techniques like the above have some problems as the following:
As a first problem, since many external interface connectors and external USB connectors are arranged in one USB unit, the number of inner connectors or other parts increases, and therefore, the USB unit increases in size and weight.
As a second problem, when the USB unit is portably carried, the USB unit has nothing but the necessary function mechanisms for a user; however, since the conventional USB unit is integrated with the conversion circuits, external interface connectors, and the like, the user must carry the USB unit with unnecessary function mechanisms. This means that the user must carry the USB unit having excessive weight.
As third problem, since the USB unit has many external interface connectors and external USB connectors for connecting a peripheral device to the USB unit, the physical amount of the inner circuits and the number of connectors increase, therefore, MTBF (Mean Time Between Failures) deteriorates.
As forth problem, since a expansion USB unit must be connected to the USB unit with a cable to extend the USB unit or the like, a space for the cable is required.